Mercedes SL review

The Mercedes SL is a car that can multitask – combining luxury with agility. It's the firm’s flagship convertible and a mainstay of the German brand’s range.

SL stands for super lightweight (a reference to the first-generation SL’s racing credentials), but this seventh-generation model is a well-equipped roadster that weighs almost two tonnes. Fortunately, Mercedes hasn't let that dent performance much. This is still a quick car.

Indeed, this is the first Mercedes SL to be developed by the car maker's high-performance subsidiary, AMG, and it gets plenty of tech to help it deliver a rewarding driver experience. We’re talking about aluminium underpinnings (to reduce weight), four-wheel drive (to improve traction) and four-wheel steering (to improve agility). Even the folding metal roof has been ditched, making way for a lighter fabric version.

Then there’s the engines. To keep up with the Aston Martin DB12 Volante, Porsche 911 Cabriolet and BMW 8 Series Convertible, the SL has four to choose from, ranging from a 4.0-litre V8 petrol right up to the mind-scrambling SL 63 S E Performance plug-in hybrid.

So we know it's powerful – but is it any good? Read on to find out how we rank the Mercedes SL against the best convertible rivals...

The Mercedes SL has always been a fine luxury roadster with a mildly sporting bent, but the latest AMG-badged version has the strongest focus on driver entertainment yet.

The entry-level SL 43's engine comes packed with power, with 376bhp courtesy of a 2.0-litre four-cylinder petrol engine. Its sub-5.0 seconds 0-62mph time makes it around half a second quicker than the BMW 840i Convertible so it’s more than quick enough, but without the fuel bills of that rival or the rest of the SL range.

That said, some buyers might be reluctant to spend six figures on an AMG-badged SL with the same engine as a Mercedes A-Class (the AMG A45 hot hatch).

The more powerful SL 55 and SL 63 have brawnier 4.0-litre petrol V8s, delivering their power through Mercedes' 4Matic+ four-wheel-drive system.

With 469bhp, the SL 55 has an abundance of power and a theatrical soundtrack to match – at our private test track we clocked one sprinting from 0-60mph in just 3.7 seconds. It’s more difficult to make a case for the SL 63, because while it produces 108bhp more than the 55, it’s only a few tenths quicker to 60mph. 

Indeed, if you’re in the market for the ultimate SL experience, we’d bypass the SL 63 and step up to the SL 63 S E Performance because its pace is nothing short of awe-inspiring. This plug-in hybrid (PHEV) range-topper features a 604bhp 4.0-litre twin-turbo V8, a 200bhp electric motor and a 4.8kWh battery, giving it a combined 805bhp. Yes, you read that correctly.

The performance figures read like a winning Top Trump card. Number of gears? Nine. 0-62mph? 2.9 seconds. Top speed? 197mph. Even the latest Bentley Continental GTC PHEV wouldn’t see which way it had gone away from the lights.

Just don’t expect the PHEV version of the SL to be frugal. With just eight miles of electric range, it used the hybrid tech for performance, not parsimoniousness.

The SL 43 comes with sports suspension as standard, while the SL 55 comes with adaptive dampers that can be softened or stiffened at the push of a button. The SL 63 and 63 E Performance get even more advanced hydraulically linked damper system. 

We’ve spent a good number of miles in the SL 55 in a variety of environments and remain impressed with how it can thrill you one moment and pamper you the next. In Comfort mode, for example, it does a fantastic job at rounding off bits of raised ironwork around town. It's more cosseting than an M850i Convertible at motorway speeds, if not quite as plush as a Continental GTC.

When you find yourself on a country road, you can knock it into Sport Plus mode and it will do a convincing impression of a proper sports car. Body control over mid-corner bumps and around off-camber corners is exceptional, and there is very little body lean. Combined with quite an aggressive rear-wheel-steering system, it feels unbelievably nimble for a convertible car of its size and weight.

The fancy set-up equipped on the SL 63 and 63 E Performance helps to make things sportier still, firming up the ride with stiffer damping for even better body control, but without compromising comfort too much. Building even further on the added sportiness is a limited-slip differential – reserved for the 63 and 63 E Performance – allowing you to easily get the monstrous power on to the tarmac with confidence.

If we had a complaint, it would be that it can take a while to dial into the steering’s quick but not particularly linear rate of response. The 911 Cabriolet has a more progressive rack and its four-wheel drive feels a touch more rear-biased, letting you play with the balance of the car on the exit of corners. And through quick changes of direction, an Aston Martin DB12 Volante feels much lighter on its feet. 

Gearshifts from the nine-speed automatic gearbox are seamlessly smooth, and while the response isn’t as instant as the PDK gearbox in the 911, it suits the character of the rest of the SL as a whole.

In terms of refinement, the SL generates a little more road roar than a Continental GTC but it’s not intrusive. With the roof up, wind noise is well contained. In fact, even with the top down, occupants are well protected from buffeting, especially with the fold-out wind-breaker fitted behind the back seats.

“The SL 63 E Performance is an outrageous car in every sense of the word. The way it can whisper through a village in silence one moment then deliver hypercar levels of straight-line acceleration the next is mind-blowing." – Neil Winn, Deputy Reviews Editor

The Mercedes SL’s interior is a mix of classic roadster proportions and modern tech. You sit low, cocooned by a tall dashboard, high window line and a broad centre console.

There’s plenty of adjustment in the electric seats and steering wheel, but visibility isn’t great. The long bonnet drops out of view, and the small rear window means you’ll be relying on the standard parking sensors and 360-degree camera more often than not.

The dashboard lay-out is clean and minimalist, dominated by an 11.9in portrait-oriented infotainment touchscreen. There are not many physical buttons, which makes for a tidy look, but it also means key functions can be tricky to find.

The screen is within easy reach and can be tilted at the press of a button to reduce glare, but its responses are sluggish. We still prefer the iDrive system in the BMW 8 Series Convertible because its rotary controller is far less distracting to use while driving.

Even something as simple as lowering the SL's roof is needlessly convoluted. The system leads you to believe you must press a physical button, then swipe and hold an icon on the touchscreen – not unlike unlocking an old iPhone. But here’s a tip: double-tap and hold the physical button, and the roof folds away without any touchscreen faff. A handy trick when you're on the move.

The four-spoke steering wheel looks busy, with touch-sensitive buttons for key driving functions, including the drive modes, spoiler and suspension settings, and stability control. The buttons are fiddly, but at least their positioning makes them easy to locate without taking your eyes off the road.

The biggest let-down? Interior quality. The SL makes a strong first impression with its ambient lighting and leather-trimmed surfaces, but some plastics feel brittle, and certain trim pieces lack the precision-fit you’d expect in a six-figure luxury roadster. 

If solidity and craftsmanship are high on your wish list, the Aston Martin DB12 Volante, BMW 8 Series Convertible and Bentley Continental GTC all do a far better job.

The BMW’s interior is rock-solid, albeit a little uninspiring in design, while the Bentley sets the benchmark with its exquisite materials and seemingly endless personalisation options. Compared with those, the SL’s interior feels disappointingly ordinary.

“The seats in the SL are hugely comfortable. I found making small tweaks to lumbar support a breeze and the chunky side bolsters do a great job of holding you tight in the bends.” – Neil Winn, Deputy Reviews Editor

There’s plenty of space for two six-foot occupants in the front of the Mercedes SL, with more than enough head, leg and elbow room.

It won’t take more than a glance at the two rear seats to realise that squeezing in four adults is ambitious, though. Those sitting up front will have to compromise their own legroom to free up a morsel of space in the rear foot well, and if the roof is up, head room in the back is limited. In fairness, this is the same with most sporty 2+2 convertibles, with the Bentley Continental GTC being the only obvious exception.

Nevertheless, if you need to take your children to nursery, or perhaps want to run your friends down to the local pub, the back seats come in handy for very short distances. You can also use them for a bit of extra storage room. 

It takes the roof 15 seconds to fold away and can be done up to 37mph. Handily, the roof stows away in its own compartment behind the seats, so it doesn’t intrude much on the 240 litre of boot space (213 litres folded).

That's not as generous as the BMW 8 Series Convertible boot (350 litres up, 280 litres folded) but comfortably beats the Aston Martin DB12 Volante (206 litres up, 169 litres folded) and Continental GTC (134 litres).

In more relatable terms, the SL has enough space for three carry-on suitcases, but as with most convertibles you’ll have to heave them over a high load lip to get them in. All SLs come with a powered boot lid.

When it comes to other storage, there’s a useful lidded cubby area that acts as a central armrest up front, and a lidded cubby by the centre touchscreen that has two small cupholders and a wireless charging tray tucked away inside.

The SL's glovebox is just big enough to store a book and the door cubbies are narrow, but it's still a car you could quite happily take on a long-distance driving holiday for two without too much fuss.

"The back seats are just about usable by children but I prefer to keep them clear for any luggage that won't fit in the boot." – Neil Winn, Deputy Reviews Editor

The Mercedes SL commands a higher price than its predecessor, with the entry-level SL 43 costing significantly more than a BMW 840i Convertible and sitting in the same price bracket as a Porsche 911 Carrera Cabriolet. At the top of the range, the SL 63 E Performance is in the same league as the Aston Martin DB12 Volante and Bentley Continental GTC.

Every version of the SL falls into the highest BIK tax bracket (paid by company car users). The SL 43’s smaller engine might suggest better fuel efficiency, but with an official figure of around 30mpg, it’s only relatively efficient compared with the V8-powered SL 55 and SL 63, which return figures in the low 20s.

What about the plug-in hybrid SL 63 E Performance? Surely that offers some tax benefits? Not really. While its 180g/km CO2 figure is 120g/km lower than the regular SL 63, it still sits in the highest BIK tax band due to its limited eight-mile electric range.

If you want a luxury convertible car with a more tax-friendly footprint, the new Bentley Continental GTC is a better bet. Its 50 miles of electric-only running and 30g/km CO2 output mean it qualifies for the much lower 8% benefit-in-kind rate – although admittedly only a lucky few will have the GTC on their company cars list.

Insurance costs for the SL are high, with all models sitting in the top insurance group. However, strong predicted resale values should help soften the blow. The SL is expected to hold its value better than the BMW 8 Series Convertible but the Porsche 911 Cabriolet is one of the strongest performers when it comes to resisting depreciation.

At least you won’t need to spend much on optional extras. Every SL comes with ambient lighting, Mercedes’ Airscarf neck heater, heated front seats and steering wheel, a Burmester sound system, sat-nav, adaptive LED headlights and dual-zone climate control as standard.

The warranty lasts three years but there’s no mileage limit. That’s useful, because Mercedes finished 22nd out of 31 manufacturers in our 2024 What Car? Reliability Survey – one place behind Porsche and well below BMW, which ranked eighth.

“I think it’s important to remember that Merc’s plug-in hybrid system has been designed to aid performance not efficiency. If you drive the SL 63 E Performance hard, you’ll see the MPG drop into the low teens" – Neil Winn, Deputy Reviews Editor

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